A 'drone' is defined an unmanned aircraft vehicle or system. This definition has two main parts: we talk about a flying object which has no pilot on board. Drones can be based on different technologies, some resemble more airplanes and have wings, others are more like helicopters with a rotor system. The latter, unlike helicopters, however, have more rotors, at least three, usually four and more. For instance a 'quadrocopter' or 'quadcopter' has four rotors and a 'hexacopter' has six rotors. Whatever the number of rotors, they are alternatively called 'multicopter' or just 'copter'.

Within this report, we focus on 'industrial drones', that is, unmanned aerial vehicles for industrial purposes only. Industrial UAV applications involve police (border inspection, forest fire prevention, traffic monitoring, flow control); energy, land and resources (inspection, planning, survey); agriculture (spraying pesticides); research and rescue, etc. These users are generally institutional customers. Their main requirements are data acquisition and transportation functions, high performance and high stability, and there are strict requirements for drone flight control, power system, and body design.